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RE: Many, many thoughts & responses re: the Hutchinson-Garcia paper - LONG

Consider this, however:  Of all the large theropods (_Carcharodontosaurus_,
_Giganotosaurus_, _Allosaurus_, etc.) _T. rex_ seems to be the one with the
MOST massive thighs and hips.  This would imply, at least as far as I can
see, that _T. rex_ could move faster than those others, because their legs
and hip structure would not allow for nearly the same amount of muscle mass
(or percentage of those muscles versus total body mass).  True, on an
absolute flat-out race between the 3 dinos I mentioned above and _T. rex_,
_Allosaurus_ MIGHT win because of the lower overall body mass.  _T. rex_
would come in second.   I would be interested to see if John would analyze
_Allosaurus_'s speed range as well, to see if my surmise is correct.

Concerning some of Dann's points below:

Hmm, why pit *Allosaurus* against the heavyweights? Would not a smaller Tyrannosaurid like *Albertosaurus* make a fairer and better choice?

The 9.1 m/s mentioned in Tom's post and Dann's are under the maximum
proposed by the Hutchinson-Garcia paper. It remains possible that this is
indeed the top-end for the safest, fastest speed by a _T. rex_, and possibly
for the Jurassic theropod as well. (This is just over 20 MPH for us
Americans :-).

What's with the safest speed limits anyway? If an animal that size fell while standing still, the damage incurred would be serious anyway. On the other hand, quite a number of animals persist in exceeding their safest survivable speed and will go on doing so, despite all your general biomechnist health warnings. ;) Try telling a falcon not to dive so fast because a one second misjudgement would mean smashing into the ground at over 200 MPH. (This is about 91 m/s for us non Amercans :-) Rather, the absolute speed the animal can possibly attain biomechnically is a better choice. Though, finding speed out by such methods is anything but easy.

Another use of _T. rex_'s massive legs could be to hold down his prey, much
like modern birds of prey do.  Jack Horner, in one of his many statements
about the poor hunting skills of _T. rex_, said "Maybe he hid behind a rock
and jumped out and kicked over a _Triceratops_!".  Ha-Ha, Jack - maybe
that's exactly what he (_T. rex_) did do!  Then, he held the animal down
(with those legs), and bit into its back and neck to kill it.

I've also thought that maybe the huge legs on _T. rex_ would make it much
easier for the animal to raise itself up from a "prone" position to stand.
(I put quotes around prone, because I think the animal couldn't lie down
completely - probably rested on the pubis, which I think would have been
very padded).

I wonder if rexy could really kick. Given the blunt and small claws and the sheer mass of the animal, I wonder if that's even possible. One of the main contentions of a certain paleontologist well known for his views on Tyrannosaurids being a poor hunter was that they were poor runners. Of course, while going into length on how slow it must have been dingdarnit, he never figures out how fast its potential prey items must have went, which is, if viewed correspondingly, actually slower then the "scavenger".

I like Currie's idea about the younger rexes doing the hunting. Of course,
it is possible that the younger ones did the chasing, and chased the prey to
the waiting adult, who provided the coup-de-grace.

Sounds good. Somehow it dosen't cause as much uproar as the idea of "pack"-hunting "raptors". Though it's not too different an idea!

Just remember, although _T. rex_ is not a speed demon, it's still a very
fast animal.  And it still is one of the most powerful of the theropods.

*T.rex* was certainly not blindingly fast in terms of sheer speed, but I believe the contention that it's probably the fastest 6-ton critter that ever lived...by a considerable margin is quite possible indeed.

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